From: David Lechner <david@xxxxxxxxxxxxxx>
From: David Lechner <dlechner@xxxxxxxxxxxx>
This modifies the ad2s1210_show_fexcit() function to read the excitation
frequency from the control register. This way we don't have to keep
track of the value and don't risk returning a stale value.
Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
---
v3 changes: None
drivers/staging/iio/resolver/ad2s1210.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 28ab877e1bc0..b15d71b17266 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -76,7 +76,6 @@ struct ad2s1210_state {
struct regmap *regmap;
/** The external oscillator frequency in Hz. */
unsigned long clkin_hz;
- unsigned int fexcit;
u8 resolution;
/** For reading raw sample value via SPI. */
__be16 sample __aligned(IIO_DMA_MINALIGN);
@@ -206,8 +205,6 @@ static int ad2s1210_reinit_excitation_frequency(struct ad2s1210_state *st,
if (ret < 0)
return ret;
- st->fexcit = fexcit;
-
/*
* Software reset reinitializes the excitation frequency output.
* It does not reset any of the configuration registers.
@@ -232,8 +229,22 @@ static ssize_t ad2s1210_show_fexcit(struct device *dev,
char *buf)
{
struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+ unsigned int value;
+ u16 fexcit;
+ int ret;
- return sprintf(buf, "%u\n", st->fexcit);
+ mutex_lock(&st->lock);
+ ret = regmap_read(st->regmap, AD2S1210_REG_EXCIT_FREQ, &value);
+ if (ret < 0)
+ goto error_ret;
+
+ fexcit = value * st->clkin_hz / (1 << 15);
+
+ ret = sprintf(buf, "%u\n", fexcit);
+
+error_ret:
+ mutex_unlock(&st->lock);
+ return ret;
}
static ssize_t ad2s1210_store_fexcit(struct device *dev,
--
2.42.0
